I’m getting the same loading time results with location turned on, so I’m not sure if the distance calculation alone is the only issue. Do you have a filter on your nearby places? I’m showing over 7000km as nearby, so it’s probably trying to load the distance for every location. You could try to temporarily not show the nearby places list, or filter it to only show locations within a reasonable distance, like 1km or 5km, but I suppose it still has to calculate for every location to find out what’s nearby.
I guess I would try different things, like not showing so many images, or not showing so much on the first screen. Create a simpler tab that shows up first to see if that makes it load faster. All computed columns run their calculations on each user’s device, so that can start to become a lot data that has to be processed and cached on each user’s device.
Just keep in mind that every user has to download all of that data and then process through any non-basic computed column every time they open the app. I have similar issues with computation heavy sheets, but they also aren’t the first thing that’s loaded in my app, so the app initially loads quickly, but it’s certain tabs to take awhile longer to load.